20 
toner's address. 
with old and cherished views that have acquired gen- 
eral acceptance. Although the late discoveries in 
phere no doubt required many centuries. Gravitation would cause 
the heavier molecules to sink dov^n to a lower strata of the atmosphere 
in which they were suspended^ and whenever they reached a temper- 
ature where repulsion ceased, and chemical affinities could act, com- 
binations would naturally be formed. And, as might be expected, 
elements in the greatest abundance, and which unite at the highest 
heat, would first form compounds and be deposited as a sort of crust 
upon the surface of the glowing and incandescent molten mass below, 
which began to form the solid surface of the earth. 
Neither carbon, sulphur, nor phosphorus, could combine at such 
high temperature. It is therefore probable that silicon with oxygen, 
and hydrogen with oxygen, which unite at high temperatures, would be 
the first combining elements. These substances, too, are so abundant 
as to form about seventy-five one-hundredths of the crust of the globe. 
The metals aluminium and potassium would pr cbably foimthe first 
combinations among the metalloids. It is not probable that any of 
the original chemical unions nov/ exist, but that all our rocks, min- 
erals, and earths are the result of metamorphic and erosive action. 
The atmosphere during the early age of the earth, it is supposed, 
was many times heavier, and of a highly acid character, which must 
have had, under the influence of heat, a formidable dissolving power. 
Oxygen, which forms about one-fifth of the whole volume of the atmos- 
phere, was, during the cosmical period, in a much larger proportion, as 
it forms: nearly two-thirds of the solid substance of the entire globe. The 
tendency is constant in the economy of nature to rob the atmosphere 
of its oxygen and to fix it in new forms, as rocks, minerals, and other 
solids of the earth. Liquid water could be formed only after the tem- 
perature of the atmosphere had fallen below 212° Fahrenheit. The 
changes that had yet to take place in the lowering of temperature, the 
purification of the water, and the m.etamorphosis of the rocks and 
their disentegration into soils before life was possible, no doubt re- 
quired many ages. 
It has been more my purpose to hint at these great cosmical epochs 
and changes than to present them in detail. I am persuaded that no 
attentive student of the form and constitution of our globe will fail to 
recognize the fact that it has been a thing of slow growth and has under- 
gone many changes. Nor can any one contemplate the plan of the 
